JP3176515B2 - Surface treated aluminum plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated aluminum plate provided with a film having lubricity on its surface, and more particularly to a molding process such as a press molding or the like, such as a chassis of a home appliance. The present invention relates to a surface-treated aluminum plate to be further coated and used later.

[0002]

2. Description of the Related Art Aluminum or aluminum alloy plates (hereinafter simply referred to as "aluminum plates") have excellent corrosion resistance and aesthetic appearance (design) and are light in weight. Widely used for etc.

[0003] However, aluminum sheets have poor formability compared to cold-rolled steel sheets and surface-treated steel sheets, and the surface layer of the material is easily peeled off by press forming or the like. There is a disadvantage that the phenomenon is also likely to occur. Further, since the hardness of the aluminum plate is lower than that of steel or the like, there is a drawback that the surface is easily scratched when formed under the same conditions as steel, and the scratch resistance is poor. For this reason, conventionally, when forming an aluminum plate, lubricating oil is applied to improve formability, and after the forming process, the aluminum plate is degreased and washed with an organic solvent to remove lubricating oil remaining on the surface. Had been done.

In recent years, the use of solvents has been regulated from the viewpoint of environmental protection and the like, and there has been a tendency to use low-viscosity volatile lubricating oils instead of conventional lubricating oils and omit the degreasing and washing step using an organic solvent. . It has also been proposed to mold without using lubricating oil. However, the effect of improving moldability is not sufficient even when a volatile lubricating oil is used, as well as when a lubricating oil is not used, and there is a problem that seizure and flaws are liable to occur during molding.

In order to solve such a problem, a film having lubricity is formed on the surface of an aluminum plate in advance, and the lubricating property at the time of forming is secured by this film to improve the formability. Treated aluminum plates have been proposed. That is, JP-A-63-59530 and JP-A-1-12
No. 2432 and Japanese Patent Application Laid-Open No. 3-134094 propose that the surface of an aluminum plate is coated with a resin mixed with a lubricant. In Japanese Patent Application Laid-Open No. 62-268636, the surface of an aluminum plate is mixed with colloidal silica. Coating with a resin has been proposed.

[0006]

However, in the method of coating the surface of the aluminum plate with a resin mixed with a lubricant, the hardness of the film is not sufficient, and the film is liable to seize at the time of forming, and the resistance to the problem is also high. There is a problem that the flawability is not sufficient. On the other hand, in the method of coating the surface of the aluminum plate with a resin mixed with colloidal silica, the seizure of the coating can be avoided and the scratch resistance is sufficient, but since the hardness of the colloidal silica is high, There is a problem that scratches are likely to occur and the mold is severely worn.

The present invention has been made in view of the above-mentioned problems, and has a high surface resistance which is high in scratch resistance, can prevent seizure at the time of molding, and can suppress abrasion of a mold. It is intended to provide an aluminum plate.

[0008]

The surface-treated aluminum plate according to the present invention is characterized in that a resin film containing talc powder having an average particle diameter of 1 to 10 μm at a ratio of 30 to 70% by weight is formed on the surface. Features.

In the present application, the aluminum plate is
An aluminum alloy plate is included in addition to a pure aluminum plate.

[0010]

The surface-treated aluminum plate according to the present invention has a resin film containing talc powder formed on the surface thereof. The talc powder has a chemical composition of hydrous magnesium silicate (3MgO ₃ .4SiO ₂ .H ₂ O) and is a hydrated compound, so that it can be easily dispersed in water.
For this reason, a treatment bath for performing the surface treatment can be easily formed, and the talc powder can be uniformly dispersed in the film. Talc powder is a relatively soft mineral having a Mohs hardness of 1.5, and has excellent wear resistance and lubricity. Furthermore, since talc powder is inert and has no hydrophilic property, the talc powder has a characteristic that the film does not deteriorate even under various environments.

Therefore, by forming a resin film containing talc powder on the surface of the aluminum plate, lubricity can be imparted to the aluminum plate, and the material (aluminum plate) slips well during molding. And the moldability is significantly improved. In addition, the talc powder dispersed in the film ensures sufficient hardness of the film, and secures more seizure during molding compared to films containing only organic compounds such as a mixture of lubricant and resin. To prevent
Scratch resistance is also improved. Furthermore, since talc powder has an extremely low hardness as compared with colloidal silica or the like, there is no possibility of causing a flaw in a molding die and the abrasion of the die is small.

The talc powder having a smaller average particle size and a smaller variation in the particle size has better abrasion and lubricity. However, when the average particle diameter of the talc powder is less than 1 μm, the dispersion of the particle diameter increases, and the abrasion and lubricity decrease. On the other hand, the average particle size of the talc powder is 10 μm.
If it exceeds m, the talc powder will be missing from the film during molding, and the film will easily peel off, and a build-up phenomenon in which the missing powder will adhere to the mold will occur. For this reason, the average particle diameter of the talc powder needs to be 1 to 10 μm.

The content of talc powder in the coating is 3%.
It needs to be 0 to 70% by weight. When the content of the talc powder in the coating is less than 30% by weight, the effect of improving the lubricity by the talc powder is not sufficient, and the effect of improving the moldability is small. In this case, the hardness of the film is not sufficient, and the film tends to seize at the time of molding, and the scratch resistance is not satisfactory. On the other hand, when the content of the talc powder in the film exceeds 70% by weight, the amount of the resin is too small to sufficiently fix the talc powder in the film, and the talc powder is missing from the film during molding. As a result, peeling of the film is likely to occur, and a build-up phenomenon occurs. For this reason, the content of the talc powder in the film needs to be 30 to 70% by weight.

Further, the thickness of the coating is preferably 1 to 15 μm, and is preferably not less than the average particle diameter of the talc powder. If the thickness of the film is less than 1 μm or less than the average particle size of the talc powder, the talc powder cannot be sufficiently fixed in the film, and the talc powder will be lost from the film during molding. On the other hand, when the thickness of the film exceeds 15 μm, the adhesion of the film is reduced, the film is liable to peel off, and the build-up phenomenon occurs.

In the present invention, the kind of the resin is not particularly limited, but is made of an epoxy resin, a urethane resin and an acrylic resin in order to secure adhesion and corrosion resistance to an aluminum plate. It is preferable to use one resin selected from the group alone, or to use a mixture of two or more of these resins.

The aluminum plate according to the present invention comprises:
The composition and the like are not particularly limited, and pure aluminum or aluminum alloy plates of various compositions can be used as long as they can be subjected to molding such as press molding.

[0017]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples that depart from the scope of the claims.

First, an aluminum alloy plate (material: 505)
2 alloy, thickness: 1 mm, temper: H32) were prepared, the aluminum alloy plate was degreased and washed with water, and then sufficiently dried. Thereafter, a film of a resin containing talc powder shown in Tables 1 to 3 below was formed on the surface of the aluminum alloy plate to obtain a surface-treated aluminum alloy plate. However, Comparative Examples 27, 55, and 83 are surface-treated aluminum alloy sheets having a resin-only film formed thereon, and Comparative Examples 28, 56, and 84 are surface-treated aluminum alloy films having a resin film containing colloidal silica instead of talc powder. Alloy plate, Comparative Examples 85 and 8
Reference numeral 6 denotes an aluminum alloy plate that has not been subjected to a surface treatment.

Next, the lubricating properties, the seizure state of the coating, and the scratch resistance of the aluminum alloy sheets of these Examples and Comparative Examples were examined by the flat plate sliding test method shown in FIG. That is, an aluminum alloy plate as the test material 3 is placed between the flat dies 1 and 2 and the die 2 is pressed toward the die 1 with a constant pressing force P, so that the test material 3 is Sandwiched between the two. Then, the test material 3 is placed in the dies 1,
2, and the drawing load F at that time was measured. The conditions at the time of the flat plate sliding test are shown below. Pressing force: 1800N Pulling speed: 300 mm / min Pulling length: 50 mm Lubrication condition: No oiling (only Comparative Example 85 is oiled with a low viscosity oil having a viscosity of 4 cst).

Then, the dynamic friction coefficient μ was calculated by the following equation 1, and the lubricity was evaluated based on the dynamic friction coefficient.

[0021]

## EQU1 ## Dynamic friction coefficient μ = F (drawing load) / 2P (pressing force)

Further, the state of seizure of the film on the surface of the test material after the flat plate sliding test was examined, and the scratch resistance was evaluated by visually observing the appearance. The results are shown in Tables 4-6.
Are shown together. However, the state of seizure of the film was indicated by ○ when no seizure occurred, Δ when slight seizure occurred, and x when significant seizure occurred. The scratch resistance was evaluated as follows: ○ when no flaw was found, Δ when small flaws occurred,
The case where a large flaw occurred was indicated by x.

Next, a cylindrical deep drawing test was performed under the following conditions, and the formability was evaluated by examining the limit drawing ratio.
The results are shown in Tables 4 to 6. Ericksen universal testing machine Wrinkle holding force; 0.6 ton Punch diameter; φ50 mm Punch shoulder R; 4.5 mm Die shoulder R; 6.0 mm Molding speed: 800 mm / min Lubrication conditions; Oil with low viscosity oil).

Next, a continuous punching test was carried out under the following conditions.
The wear of the mold was evaluated. The results are shown in Tables 4 to 6. However, in the abrasion evaluation, the weight reduction rate was 30 p.
pm or less is indicated by ○, more than 30 ppm and less than 100 ppm is indicated by Δ, and more than 100 ppm is indicated by ×. Punch diameter: φ30 mm Die diameter: φ32 mm Punch shoulder R: 1.0 μm or less Dice shoulder R: 1.0 μm or less Punch weight: 1000 g Molding speed: 300 spm Lubrication conditions: No oiling (only low viscosity oil of Comparative Example 85 has a viscosity of 4 cst) Oiling)

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

[0029]

[Table 5]

[0030]

[Table 6]

As is clear from Tables 4 to 6, Examples 1 to
12, 29 to 40, and 57 to 68 all have low dynamic friction coefficients of 0.12 or less, and good results are obtained in all of moldability, scratch resistance and abrasion of a molding die. Seizure was also prevented. On the other hand, Comparative Example 13,
15, 17, 19, 41, 43, 45, 47, 69, 7
For 1,73,75, the talc powder content in the film was 20%
, The lubricating property was insufficient and the effect of improving the moldability was not satisfactory, and seizure of the film occurred, and the film hardness was too low, so that the scratch resistance was not satisfactory.

Comparative Examples 14, 16, 18, 20, 42, 4
In 4,46,48,70,72,74,76, the content of talc powder in the film was too high as 80%, so that the powder was missing during the molding process and the film was seized.
Further, the abrasion of the mold was not satisfactory.

Comparative Examples 21 to 23, 49 to 51, 77 to 7
In No. 9, since the average particle diameter of the talc powder was as small as 0.5 μm and the particle diameter was large, the lubricating property was not sufficient, and the moldability and the wear of the mold were not satisfactory.

Comparative Examples 24-26, 52-54, 80-8
In No. 2, the average particle diameter of the talc powder was too large, 20 μm, so that the powder was missing during the molding process, and the coating was seized. In addition, the wear of the mold was not satisfactory.

Comparative Examples 27, 55 and 83 are films made of only resin, and have a large dynamic friction coefficient and poor lubricity.
Significant seizure occurred. In addition, since the film hardness was too low, the scratch resistance was not satisfactory.

Comparative Examples 28, 56, and 84 were films containing colloidal silica, and had good lubricity and moldability, but extremely poor mold wear.

Comparative Example 85 in which a low-viscosity oil was applied had extremely poor scratch resistance, seizure of the film occurred, and the abrasion of the mold was not satisfactory. Comparative Example 86 which is an untreated material
The film had remarkable seizure of the film and extremely poor scratch resistance.

[0038]

As described above, the surface-treated aluminum plate according to the present invention is provided with a resin film containing talc powder on its surface, so that the hardness of the film is high.
The lubricating property, moldability, and scratch resistance are good, seizure can be prevented, and the abrasion of the mold can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a flat plate sliding test method.

[Explanation of symbols]

 1, 2; flat plate die 3; test material

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI B32B 27/40 B32B 27/40 (58) Field surveyed (Int.Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (2)

(57) [Claims] 1. A surface-treated aluminum plate having a surface coated with a resin film containing talc powder having an average particle diameter of 1 to 10 μm at a ratio of 30 to 70% by weight. 2. The surface-treated aluminum plate according to claim 1, wherein the resin is at least one resin selected from the group consisting of an epoxy resin, a urethane resin, and an acrylic resin.